Mulch tower treatment system for greywater reuse Part II: destructive testing and effluent treatment
- Authors: Tandlich, Roman , Zuma, Bongumusa M , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71547 , vital:29863 , https://doi.org/10.1016/j.desal.2008.03.031
- Description: The mulch tower (MT) system described in Part I was tested to failure to determine its range of operating conditions. An increase in the influent temperature led to a statistically significant release of components of the chemical oxygen demand (COD) and the five day biochemical oxygen demand (BOD5), as well as phosphates from the MT system. Heterotrophic plate count (HPC) of the mulch layer dropped from 1.2 (± 0.6) × 106/g dry weight to 1.5 (± 0.3) × 105/g dry weight of the mulch layer with increases of the influent temperature. This indicates that the increase in influent temperature killed off some of the active biomass in the MT biofilm. After a five day drying period under active aeration, the MT system retained the ability to remove COD, total suspended solids (TSS), and nitrates. Greywater treatment by the MT system became impossible after a 48 day drying period under active aeration. Chlorination of the simulated MT effluent with a mixture of sodium dichloroisocyanurate and trichloroisocyanuric acid decreased the faecal coliform concentrations (FC) and the total coliform concentrations (TC) below 800 CFUs/100 ml within 65 h. Beyond 65 h, the pH of the effluent became highly acidic. To maintain optimum performance influent should be fed into the MT system at least once every 5 days, sufficient aeration should be guaranteed, and the MT effluent should be chlorinated for 65 h to eliminate all pathogens before any reuse.
- Full Text: false
- Date Issued: 2009
Mulch tower treatment system Part I: Overall performance in greywater treatment
- Authors: Zuma, Bongumusa M , Tandlich, Roman , Whittington-Jones, Kevin J , Burgess, Jo E
- Date: 2009
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71537 , vital:29862 , https://doi.org/10.1016/j.desal.2008.03.030
- Description: A mulch tower (MT) system for greywater treatment is introduced in this paper. Materials used to assemble the MT system included mulch, coarse sand, fine and coarse gravel. Limited removal efficiency of the MT system was demonstrated for alkalinity, total hardness, pH, Cl–, PO43–, NH4+, and SO42–, with the estimated cumulative removals ranging from 7 to 12%. Intermediate removal efficiency was observed for chemical oxygen demand (COD), NO3–, and S2– with the estimated cumulative removals ranging from 24 to 28%. The highest removal efficiency was observed for the total suspended solids (TSS) with the estimated cumulative removal equal to 52%. Given the minute residence time in the MT system, the results obtained were promising and justify scale-up studies for potential on-site applications. The MT effluent did not meet hygienic norms with respect to the faecal coliform concentration (FC) and the total coliform concentration (TC), and further effluent treatment is required before any discharge or reuse of the treated greywater. Further research should focus on characterisation of the microbial community of the MT, and the fate of Cl–, PO43–, NH4+, and SO42–.
- Full Text: false
- Date Issued: 2009
Hydrolytic enzymes in sewage sludge treatment: a mini-review
- Authors: Burgess, Jo E , Pletschke, Brett I
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6478 , http://hdl.handle.net/10962/d1006166 , http://hdl.handle.net/10520/EJC116535
- Description: Biological wastewater treatment processes can be classified as either aerobic or anaerobic. These two biological treatment processes are each characterised by groups of micro-organisms and their associated enzymes. Hydrolytic enzymes secreted by these micro-organisms are vital for the rate-limiting step of hydrolysis in the treatment of highly polymeric substrates present in sewage sludge. In this mini-review, the effects of mass transfer limitation, metabolic intermediates, extracellular polymeric substances (EPS), electron acceptor conditions and pH and temperature on the activity of these enzymes are summarised. The most salient and current perspectives of the significance and the role that hydrolytic enzymes play in sewage sludge treatment are highlighted.
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- Date Issued: 2008
The effects of increased freshwater inflow on metal enrichment in selected Eastern Cape estuaries, South Africa
- Authors: Orr, Kyla K , Burgess, Jo E , Froneman, P William
- Date: 2008
- Language: English
- Type: Article
- Identifier: vital:6967 , http://hdl.handle.net/10962/d1012032
- Description: The concentrations of select metals (Cd, Co, Cu, Fe, Pb, Ni and Zn) within the water column and sediment of the permanently open Kariega Estuary and temporary open / closed Riet and East Kleinemonde Estuaries were investigated during a dry and a wet season. Enrichment factors (EFs), using Fe as a reference element, and baseline linear regression models for metals vs Fe were used to assess the extent of metal enrichment in the sediments. The results of the study indicate that Cd, Co Ni and Pb were enriched above baseline concentrations (1.0 < EF < 4.1) in the sediments of all three estuaries. Co, Pb and Ni enrichment in the Kariega Estuary sediments was significantly higher during the dry season, and the mean concentrations of Pb and Cd in the water column were 19-fold and 66-fold higher in the dry season. The elevated concentration of metals during the dry season could be related to accumulation of diffuse pollution from human activities within the catchment area. Conversely, inflow of freshwater into the estuary had the net effect of reducing the concentration and enrichment of these metals within the Kariega Estuary due to scouring and outflow of estuarine water and sediment into the marine environment. The temporal variations in metal concentrations and enrichment factors were less pronounced in the temporary open / closed estuaries than the Kariega Estuary. The observed trend can probably be related to the low anthropogenic impact within the catchment areas of these systems, and the relatively smaller size of the catchments. Significant spatial variations existed in metal enrichment in the sediment of both the East Kleinemonde and Riet Estuaries, with the highest degrees of enrichment occurring in the sediments from the marine environment and lower reaches.
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- Date Issued: 2008
Anaerobic digestion of fungally pre-treated wine distillery wastewater
- Authors: Melamane, Xolisa L , Tandlich, Roman , Burgess, Jo E
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/71740 , vital:29932 , https://doi.org/10.5897/AJB2007.000-2305
- Description: The combination of fungal pre-treatment with Trametes pubescens and anaerobic digestion were tested for the removal of chemical oxygen demand (COD) and phenolic compounds from wine distillery wastewater. The COD removal efficiency after fungal pre-treatment reached 53.3%. During digestion, pH buffering was achieved using CaCO3 and K2HPO4. This provided a stable environment inside digester for efficient and time-independent COD removal. The total COD removal efficiency reached 99.5%, and the system proved able to eliminate shock COD loads, as indicated by the concentrations of sludge and volatile fatty acids. Complex changes of phenolic compounds are suspected in anaerobic digestion system, and are investigated further.
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- Date Issued: 2007
Bioremediation of trace organic compounds found in precious metals refineries wastewaters: A review of potential options
- Authors: Barbosa, V L , Tandlich, Roman , Burgess, Jo E
- Date: 2007
- Language: English
- Type: Article
- Identifier: vital:6469 , http://hdl.handle.net/10962/d1005798 , http://dx.doi.org/10.1016/j.chemosphere.2007.01.018 , http://www.sciencedirect.com/science/article/pii/S0045653507001026
- Description: Platinum group metal (PGM) refining processes produce large quantities of wastewater, which is contaminated with the compounds that make up the solvents/extractants mixtures used in the process. These compounds often include solvesso, β-hydroxyxime, amines, amides and methyl isobutyl ketone. A process to clean up PGM refinery wastewaters so that they could be re-used in the refining process would greatly contribute to continual water storage problems and to cost reduction for the industry. Based on the concept that organic compounds that are produced biologically can be destroyed biologically, the use of biological processes for the treatment of organic compounds in other types of waste stream has been favoured in recent years, owing to their low cost and environmental acceptability. This review examines the available biotechnologies and their effectiveness for treating compounds likely to be contained in precious metal extraction process wastewaters. The processes examined include: biofilters, fluidized bed reactors, trickle-bed bioreactors, bioscrubbers, two-phase partitioning bioreactors, membrane bioreactors and activated sludge. Although all processes examined showed adequate to excellent removal of organic compounds from various gaseous and fewer liquid waste streams, there was a variation in their effectiveness. Variations in performance of laboratory-scale biological processes are probably due to the inherent change in the microbial population composition due to selection pressure, environmental conditions and the time allowed for adaptation to the organic compounds. However, if these factors are disregarded, it can be established that activated sludge and membrane bioreactors are the most promising processes for use in the treatment of PGM refinery wastewaters.
- Full Text:
- Date Issued: 2007
Submerged membrane bioreactor and secondary digestion for the treatment of wine distillery wastewater: Part I: Raw wine distillery wastewater digestion
- Authors: Melamane, Xolisa L , Tandlich, Roman , Burgess, Jo E
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76139 , vital:30511 , https://www.prt-parlar.de/download_feb_2007/
- Description: A combination of a submerged membrane bioreactor (SMBR) and a secondary digester was tested for the treatment of wine distillery wastewater (WDW). The experimental system, consisting of four individual reactors, was tested during a 30-days study. Buffering of pH was achieved by mixing the feed stream of the system with 1000 mg/l of CaCO3 and K2HPO4 for the initial 10 days of the bioreactor system operation, and with 8000 mg/l of CaCO3 and 4000 mg/l of K2HPO4 for the remainder of the study. Buffering proved to be significant for optimum performance of the system in removal of soluble chemical oxygen demand (CODS), and volatile fatty acids (VFAs). Different batches of WDW used for feeding the reactor had variable compositions with respect to concentrations of nitrates, ammonium and the total concentration of phenolic compounds. Am-monium accumulated in the secondary digester after 14 days of treatment system operation, indicating the time required for the establishment of anaerobic conditions in the system. An additional step would be required for removal of phosphates from the effluent of the bioreactor, e.g., reverse osmosis, if the effluent is to be reused in production or other applications.
- Full Text:
- Date Issued: 2007
Submerged membrane bioreactor and secondary digestion in the treatment of wine distillery waste: Part II: the effect of fungal pre-treatment on wine distillery wastewater digestion
- Authors: Melamane, Xolisa L , Strong, Peter James , Tandlich, Roman , Burgess, Jo E
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/76150 , vital:30514 , https://www.prt-parlar.de/download_feb_2007/
- Description: The effect of fungal pre-treatment using Trametes pubescens on the anaerobic digestion ultrafiltration treatment of wine distillery wastewater (WDW) was studied. The downstream biological treatment system, consisting of four individual reactors, was operated for 30 days. pH buffering was achieved by mixing the pre-treated system feed with CaCO3 and K2HPO4; this proved significant for optimum performance of the system in removal of soluble chemical oxygen demand (CODS). The experimental system was shown to eliminate an average of 86 (± 4) % of CODS present in the pre-treated WDW. Treatment in a submerged membrane bioreactor (SMBR) and subsequent secondary digester, together with pH buffering using CaCO3 and K2HPO4, led to the stabilisation of CODS removal. The residual CODS levels in the final effluent were approximately 400 mg/l, significantly lower than the concentrations observed when treating raw WDW, indicating that fungal pre-treatment might have provided additional nutrients for removal of recalcitrant components of the wastewater. The resulting effluent of the system is rich in nitrates and phosphates. Together with the residual organic content it might be used as a fertiliser. Alternatively, if water management of the wine distillery is an issue, a membrane process, such as reverse osmosis or nanofiltration could be applied to bring the parameters of the water to meet the technological needs.
- Full Text:
- Date Issued: 2007
Treatment of wine distillery wastewater by high rate anaerobic digestion
- Authors: Melamane, Xolisa L , Tandlich, Roman , Burgess, Jo E
- Date: 2007
- Language: English
- Type: text , article
- Identifier: http://hdl.handle.net/10962/75896 , vital:30480 , https://doi.org/10.2166/wst.2007.466
- Description: Wine distillery wastewaters (WDW) are acidic and have a high content of potential organic pollutants. This causes high chemical oxygen demand (COD) values. Polyphenols constitute a significant portion of this COD, and limit the efficiency of biological treatment of WDWs. WDW starting parameters were as follows: pH 3.83, 4,185 mg/l soluble COD (CODs) and 674.6 mg/l of phenols. During operation, amendments of CaCO3 and K2HPO4, individually or in combination, were required for buffering the digester.
- Full Text: false
- Date Issued: 2007
Biological removal of nitrogen species from metal-processing wastewater
- Authors: Kasia, J M , Duncan, John R , Burgess, Jo E
- Date: 2005
- Language: English
- Type: Article
- Identifier: vital:6482 , http://hdl.handle.net/10962/d1006256
- Description: Although several nitrification/denitrification processes are established for the removal of ammonia and nitrate from municipal and industrial wastewaters, there are few reported results on the removal of these ions from metal-processing and finishing wastewaters. Unlike municipal wastewater, there is very little organic content in metal-processing wastewaters. Sources of ammonia and nitrate in the wastewater include the use of ammonium-nitrate-fuel oil as a blasting agent, and the use of other nitrogen-containing reagents during processing. The objective of this work was to investigate a biological process for the removal of nitrogenous compounds from real metal-processing wastewater. The system comprised an aerobic continuously stirred tank reactor (CSTR) followed by an anaerobic packed column and was run using real wastewater from a metal-processing operation. The system was inoculated using humus sludge from a municipal trickling filter and a period of approximately four weeks was required for a denitrifying biofilm to develop. Results showed that ammonia removal occurred readily in the CSTR while nitrite oxidation was slower to develop. The CSTR was found to be suitable for ammonia oxidation; up to 89% ammonia removal was achieved. By employing an integrated process comprising nitrification and denitrification, high ammonia removal efficiencies can be obtained. An effluent that is low in ammonia can be obtained with this system with additional carbon introduced after the CSTR. The gravel-packed column reactor was found to be unsuitable for the removal of nitrate in the configuration used (maximum 15% removal efficiency). The critical parameters for denitrification are nitrate concentration, temperature, influent flow rate and mean cell retention time. Nitrate removal did not meet the expectations projected by previous authors' work using synthetic wastewater.
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- Date Issued: 2005